I feel like Bloodline Keeper is a bit too slow for Modern especially given your lack on 1-mana creatures. I don't think you need Rakish Heir or Stensia Masquerade either; you have plenty of pump as it is. Instead, try adding more low-costed creatures like more Stromkirk Noble, Vampire Lacerator, Vicious Conquistador, or Bloodghast.

Feast of Blood is awful. It really is. It's slow, it's situational, it's sorcery speed. Try instead Fatal Push and trade up for some fetch lands and add some Blood Crypts. Blackcleave Cliffs is also so much better than Dragonskull Summit if you can afford them. On the subject of removal, Gatekeeper of Malakir is insane. 3 mana for a chainer's edict with a 2/2 body and tribal support.

If you dropped a few of your heavier-costed cards you could look into a single copy of Olivia Voldaren, Kalitas, Traitor of Ghet or Sanctum Seeker depending on how aggro you want to go. Other support lands to consider, largely depending on your budget are Urborg, Tomb of Yawgmoth, Cavern of Souls, and Mutavault.